Examples of conventional air bag apparatuses for a driver seat include an air bag apparatus incorporated in, for example, the steering wheel of an automobile and adapted to inflate a pouch-shaped air bag with gas flowing into the air bag so as to reduce a shock delivered to the driver of the automobile as a result of a collision. The air bag used for such an air bag apparatus is formed into a flat bag by sewing a pair of circular bag materials (panels) together along the edge. Each bag material is a geowoven made of a polyamide-based synthetic fiber. The air bag has a mounting hole which is formed in the bag material located at the side that faces the body of the vehicle so as to introduce gas into the air bag. The air bag is stored in the steering wheel in such a state that the air bag is folded into a compact shape with the material around the mounting hole affixed to the body of the steering wheel. When the inflator is actuated, the pressure of the gas ejected from the inflator expands the air bag toward the driver so as to receive and hold the driver, who has been thrown forward, thereby reducing the shock delivered to the driver.
An air bag having the configuration described above is required to inflate widely and flatly, and various structures to meet this requirement have heretofore been offered. For example, a configuration which calls for connecting the bag material at the driver side and the bag material at the vehicle side together by means of a tether belt is widely known to those skilled in the art. Furthermore, as described in Japanese Patent Laid-open No. 50437-1973, Japanese Patent Gazette No. 2631300 and the specification of European Patent No. EPO775614A2, another typical configuration well known to those skilled in the art calls for connecting the bag material at the driver side to the bag material at the vehicle side with a cloth which is provided with a gas flow-through hole, and introducing the gas ejected from the inflator into a plurality of sections inside the air bag, wherein the gas is introduced into the sections in sequence, from one section to another. These configurations are intended to effectively hold an occupant who sits in a normal position by limiting the shape into which the air bag may be inflated. Other known examples of the conventional art include a configuration described in Japanese Patent Laid-open No. 192703-1996, which includes cloth panels designed to control the flow of gas in such a way that the gas flows in the direction of the outer edge of the air bag. Yet another example, which is disclosed in Japanese Utility Model Publication No. 11084-1986, calls for dividing the interior of the pouch-shaped air bag into sections with sectioning members, which are connected to a gas supply opening by means of such an expansion limiting member as a belt.
Nowadays, there is a demand for an air bag apparatus which is capable of controlling the process of expansion of the air bag and reducing the pressure applied to an occupant even if the occupant is out of position, in other words the occupant is extremely close to the air bag apparatus or at any other out of the ordinary position.
In order to solve the above problems, an object of the present invention is to provide an air bag which is capable of controlling the shape of the air bag and the pressure to be applied to various locations of the air bag throughout the process of expansion of the air bag, and obtaining superior shock absorption characteristics